JP2005083859A - Network assistance type gps terminal and positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an A-GPS terminal which is reduced in communication frequency concerning an approximate position. <P>SOLUTION: The A-GPS terminal obtains position information of a cell currently belonging as an approximate position from a network 2, in which position information of a plurality of cells is registered, in advance and has an approximate position holder 46, a GPS part 43 conducting GPS positioning, and a communication part 41 capable of receiving cell information capable of identifying a self-cell informed in each cell within individual cells. It also has a control part 42 which in the case of the first GPS positioning, or when the cell information received with the communication part 41 in the second and further GPS positioning is different from the previous GPS positioning, an approximate position is obtained from the network 2, supplies it to the GPS part 43 and make an approximate position holder 46. When the cell information received with the communication part 41 in the second and further GPS positioning is the same as the previous GPS positioning, the approximate position held in the approximate position holder 46 is supplied to the GPS part 43. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a GPS (Global Positioning System) terminal, and more particularly to an A-GPS (Network Assisted GPS) terminal. Further, the present invention relates to a position positioning method performed in such an A-GPS terminal and a program thereof.

  In recent years, as a GPS system for mobile terminals, an A-GPS system (see, for example, Patent Document 1) that enables high-sensitivity and high-speed positioning that is difficult with a single terminal by receiving assist data from a network has become mainstream. Yes. In general, there are three pieces of information necessary as assist data: a navigation message (Almanac, Ephemeris, etc.), GPS time, and an approximate position of a mobile terminal.

  FIG. 8 shows an outline of a positioning system using a conventional A-GPS system. This positioning system includes a network 2 which is a digital network (public network), a plurality of radio base stations 3a and 3b connected to the network 2, a positioning server 1 installed on the network 2, and each radio base station 3a. And 3b cells (wireless communication areas) A and B, which are portable terminals 100 and 101 capable of wireless communication. The mobile terminals 100 and 101 are both GPS terminals capable of positioning by the A-GPS method. FIG. 8 shows a state where the mobile terminal 100 is located in the cell A and the mobile terminal 101 is located in the cell B.

  The positioning server 1 always grasps signals from a large number of GPS satellites in an ideal state, and demodulates the navigation messages and GPS signals for capturing the GPS satellites to the mobile terminals 100 and 101, respectively. Has the function of supplying the GPS time. The network 2 is pre-registered with cell location information of each of the radio base stations 3a and 3b, and has a function of supplying to the mobile terminals 100 and 101 the location information of the cell that currently belongs as the approximate location of the own terminal. . The mobile terminal 100 is supplied with an approximate position 102, which is the current approximate position of the terminal itself, from the network 2 via the radio base station 3a. Similarly, the mobile terminal 101 is supplied with an approximate position 103, which is the current approximate position of the terminal itself, from the network 2 via the radio base station 3b. Here, the approximate positions 102 and 103 are positions (cell positions) of cell centers (generally sector centers) in consideration of antenna directivity. In addition, it can replace with this cell position and the positional information (longitude, latitude) of a wireless base station can also be used.

In the above positioning system, when a predetermined input operation for positioning the current position of the terminal is performed on the mobile terminal 100, the approximate position 102 supplied from the network 2 and the navigation message supplied from the positioning server 1 are used. Based on the above, GPS satellites necessary for positioning are captured, and GPS signals received from the captured GPS satellites are demodulated based on the GPS time supplied from the positioning server 1. The mobile terminal 101 can perform similar satellite acquisition and GPS signal demodulation.
JP 2003-43127 A

  However, in the conventional positioning system described above, the mobile terminal (GPS terminal) needs to acquire assist data (navigation message, GPS time, and approximate position) via the network every time positioning is performed. As described above, acquiring assist data from the network every time positioning results in an increase in positioning time and network traffic due to data communication, and an increase in cost when data communication is charged. It will also be. For this reason, in the A-GPS system, how to reduce the frequency of assist data communication is an important issue.

  Among the assist data, the navigation message has a data valid period of about several hours. During this valid period, the navigation message is held on the GPS terminal side, and satellite acquisition is performed using this held navigation message. It is possible. This eliminates the need to receive a navigation message from the network for each positioning. As for the GPS time, it is not necessary to receive the GPS time from the network by holding the GPS time using a crystal oscillator or the like on the GPS terminal side. However, in consideration of the case where the GPS terminal moves at a high speed, it is necessary to receive the approximate position from the network for each positioning. Up to now, no method has been proposed for solving the problems of the increase in positioning time, the increase in network traffic, and the increase in cost due to the above-mentioned data communication regarding the approximate position.

  An object of the present invention is to provide a network-assisted GPS terminal, a position positioning method, and a program that can solve the above-described problems and reduce the frequency of communication with the network for an approximate position.

In order to achieve the above object, the network-assisted GPS terminal of the present invention is an estimate that is one of assist data for performing GPS positioning from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. A network-assisted GPS terminal that acquires location information of a cell that currently belongs as a location,
A holding unit for holding the approximate position;
A GPS unit that performs the GPS positioning based on the assist data;
A communication unit capable of receiving, in each cell, cell information capable of identifying the own cell broadcasted in each of the plurality of cells;
When performing the first GPS positioning, or when the cell information received by the communication unit in the second and subsequent GPS positioning is different from the previous GPS positioning, the approximate position is acquired from the network, and the acquisition is performed. When the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position is supplied to the GPS unit and held in the holding unit. And a controller that supplies the approximate position being held to the GPS unit.

Another network-assisted GPS terminal according to the present invention is a cell that currently belongs as an approximate position that is one of assist data for performing GPS positioning from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. A network-assisted GPS terminal that acquires location information of
A holding unit for holding the approximate position;
A GPS unit that performs the GPS positioning based on the assist data;
A communication unit capable of receiving, in each cell, cell information capable of identifying the own cell broadcasted in each of the plurality of cells;
A storage unit for storing cell information received by the communication unit as internal cell information;
A timer unit for measuring a predetermined time;
When the cell information received by the communication unit is different from the previously received cell information stored in the storage unit, the timer unit is activated, and the activated timer unit times out A control unit that maintains the state in which the internal cell information, which is the cell information received last time, is stored in the storage unit.
When the control unit performs the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positionings, the approximate position from the network And the obtained approximate position is supplied to the GPS unit and held in the holding unit, and the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning. In this case, the approximate position held in the holding unit is supplied to the GPS unit.

  In the positioning system of the present invention, position information of a plurality of cells constituting a wireless area is registered in advance with any of the above-described network-assisted GPS terminals, and the GPS terminal has a cell to which the terminal currently belongs. And a network for supplying position information.

In the position positioning method of the present invention, the position information of a cell that currently belongs as an approximate position that is one of assist data for performing GPS positioning is obtained from a network in which the position information of a plurality of cells constituting a wireless area is registered in advance. A positioning method performed in a network-assisted GPS terminal to be acquired,
A communication unit provided in the GPS terminal and capable of receiving in each cell the cell information capable of identifying its own cell broadcasted in each of the plurality of cells receives the cell information in the cell to which it currently belongs. And steps to
When the control unit provided in the GPS terminal performs the first GPS positioning, or when the cell information received by the communication unit in the second or subsequent GPS positioning is different from the previous GPS positioning, the network If the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position is acquired from the holding unit provided in the GPS terminal, And using the approximate position held in the holding unit as the assist data.

According to another position positioning method of the present invention, a position of a cell that currently belongs as an approximate position that is one of assist data for performing GPS positioning from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. A position positioning method performed in a network-assisted GPS terminal that acquires information,
A communication unit provided in the GPS terminal and capable of receiving in each cell the cell information capable of identifying its own cell broadcasted in each of the plurality of cells receives the cell information in the cell to which it currently belongs. And steps to
A storage unit provided in the GPS terminal stores the cell information received by the communication unit as internal cell information;
The control unit provided in the GPS terminal is provided in the GPS terminal when the cell information received by the communication unit is different from the internal cell information which is the previously received cell information stored in the storage unit. Starting the timer unit that measures the predetermined time, and maintaining the state in which the internal cell information, which is the cell information received last time, is stored in the storage unit as it is until the started timer expires When,
When the control unit performs the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positionings, the approximate position from the network Is acquired and held in the holding unit provided in the GPS terminal, and the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the And using the stored approximate position as the assist data.

The program of the present invention acquires position information of a cell that currently belongs as an approximate position that is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. A program used in a network-assisted GPS terminal,
A process for causing a communication unit capable of receiving in each cell cell information capable of specifying its own cell broadcasted in each of the plurality of cells to receive the cell information in a currently belonging cell;
When the first GPS positioning is performed, or when the cell information received by the communication unit in the second and subsequent GPS positioning is different from the previous GPS positioning, the approximate location is obtained from the network and the GPS terminal When the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position held in the holding unit is stored in the assist data. The GPS terminal computer is caused to execute processing used as

Another program of the present invention uses the network in which the location information of a plurality of cells constituting a wireless area is registered in advance as the approximate location, which is one of assist data for performing GPS positioning, as the location information of the currently belonging cell. A program used in a network-assisted GPS terminal to obtain,
A process for causing a communication unit capable of receiving in each cell cell information capable of specifying its own cell broadcasted in each of the plurality of cells to receive the cell information in a currently belonging cell;
Processing to store the cell information received by the communication unit in the storage unit as internal cell information;
When the cell information received by the communication unit is different from the internal cell information which is the previously received cell information stored in the storage unit, the timer unit for measuring a predetermined time is activated, and the activated timer is Until the time is up, a process of maintaining the state in which the internal cell information which is the previously received cell information is stored in the storage unit, and
When performing the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positioning, the approximate position is acquired from the network and retained. When the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position stored in the holding unit is used as the assist data. Are executed by a computer of the GPS terminal.

  The above-described network-assisted GPS terminal, position positioning method, and program of the present invention have the following effects.

  Since the approximate location supplied as assist data from the network is the location information location of the cell to which it currently belongs (or the location information of the radio base station that has jurisdiction over that cell), it is always the same while moving within the same cell. An approximate position will be supplied. The present invention pays attention to this point, and in the second and subsequent positioning within the same cell, positioning is performed by using the approximate position at the previous positioning (stored in the terminal). No need to receive an approximate location from the network. Therefore, the communication frequency of the approximate position is less than that of the conventional one. Whether it is in the same cell is recognized from a change in cell information.

  Moreover, in the other network-assisted GPS terminal, the other positioning method and the other program of the present invention described above, the following operation is also obtained in addition to the above operation.

  In the case where the approximate position is acquired from the network at the timing of the change of the cell information, it is expected that the cell information frequently changes when the GPS terminal is located near the cell boundary, and the communication frequency of the approximate position increases. It is possible. According to the present invention, the approximate position is acquired from the network when not the cell information but the internal cell information changes. The internal cell information stores the received cell information. However, when the cell information changes, the previous cell information is maintained as it is until a predetermined time elapses from the timing of the change. ing. For example, when the cell information is changed from the cell A to the cell B and then changed to the original cell A before a predetermined time elapses, the internal cell information is maintained as information about the cell A. Therefore, even if the cell information changes frequently, as long as the internal cell information does not change, the approximate location from the network is not acquired.

  According to the present invention, since the communication frequency of the approximate position is less than the conventional one, the network traffic is reduced, and the communication cost can be kept low when the data communication is charged.

  In addition, the GPS positioning time can be shortened by using the approximate position at the time of the previous GPS positioning stored in the terminal.

  In addition, in the case where the internal cell information is not changed for a predetermined time even if the cell information changes, the communication frequency related to the approximate position when the cell information changes frequently can be reduced. The effect of reducing communication costs can be further increased.

(First embodiment)
FIG. 1 shows a position positioning system including an A-GPS terminal according to the first embodiment of the present invention. In FIG. 1, the positioning server 1, the network 2, and the radio base station 3 are the same as those shown in FIG. 8, and detailed description thereof will be omitted here.

  The A-GPS terminal 4 of the present embodiment captures satellites (usually three or more GPS satellites are captured) and GPS signals based on assist data (navigation message, GPS time, approximate position) received from the network 2. Mobile communication terminals (including mobile phones and in-vehicle terminals) whose main parts are a communication unit 41, a control unit 42, a GPS unit 43, a GPS time holding unit 44, a navigation message holding unit 45, An approximate position holding unit 46 is included.

  The communication unit 41 performs wireless communication with the wireless base station 3 in the cell (wireless communication area) of the wireless base station 3. The control unit 42 acquires assist data from the network 2 and registers the position in the network 2 via the communication unit 41. In addition, the control unit 42 holds GPS time in the assist data in the GPS time holding unit 44, holds the navigation message in the navigation message holding unit 45, holds the approximate position in the approximate position holding unit 46, and holds these The update of the retained data in each unit is individually controlled. Further, the control unit 42 supplies the acquired assist data to the GPS unit 43 at the time of positioning, or reads the holding data from each holding unit 44 to 46 and supplies it to the GPS unit 43 as necessary.

  The navigation message holding unit 45 holds a navigation message in the acquired assist data for a predetermined time. Here, the fixed time is the data valid period of the navigation message. In the case of “Almanac” data, the data validity period is several weeks, and in the case of “Ephemeris” data, the data validity period is 30 minutes to 1 hour. When the data valid period has passed, the navigation message holding unit 45 holds a navigation message newly acquired from the network 2 in place of the navigation message held so far. In this way, the navigation message holding unit 45 always holds a valid navigation message. The navigation message updating operation is also controlled by the control unit 42.

  The GPS time holding unit 44 holds the GPS time acquired as assist data using, for example, a crystal oscillator. The GPS time is acquired as assist data from the network 2 only at the start of positioning and is held by the GPS time holding unit 44. Thereafter, the GPS time generated by the GPS time holding unit 44 is used as assist data. .

  The approximate position holding unit 46 holds the approximate position of the acquired assist data during the period when the A-GPS terminal 4 is in the same cell. When the A-GPS terminal 4 moves to another cell, the approximate position holding unit 46 holds the approximate position newly acquired from the network 2 instead of the approximate position that has been held so far. Thus, the approximate position holding unit 46 always holds the approximate position in the cell where the A-GPS terminal 4 is currently located. The update operation of the approximate position is also controlled by the control unit 42.

  The GPS unit 43 includes a well-known GPS receiver, and captures the GPS satellite 5 using assist data acquired from the network 2 or assist data held in the holding units 44 to 46 and the captured GPS satellite 5. The GPS signal is received from and demodulated. The positioning result thus demodulated and generated is passed to the control unit 42.

  Next, a specific positioning operation of the A-GPS terminal 4 will be described. The most characteristic operation of the A-GPS terminal 4 is that the estimated position is maintained and reused while moving in the same cell. As described in the above-mentioned problem, the navigation message retention and the GPS time retention are operations that have been performed in the past. Therefore, detailed explanation of these operations is omitted here, and the approximate position that is a feature point is retained. The operation will be mainly described.

  FIG. 2 shows one procedure of the positioning operation of the A-GPS terminal 4. During normal standby (non-positioning), the control unit 42 performs location registration in the network 2 via the communication unit 41 and uses the location registration information to obtain cell information (number or cell identification number). Changes in the position information are monitored (step S10). Here, the location registration is well-known location registration performed in, for example, a mobile communication system using a cell system, and the location registration information includes information on a cell to which the A-GPS terminal 4 currently belongs. Usually, for each radio base station, the cell information of the own station is constantly broadcast using a preset broadcast channel, and the communication unit 41 receives the cell information broadcast in each cell. Can do. In the A-GPS terminal 4, the control unit 42 acquires the notified cell information via the communication unit 41, compares the acquired cell information with the previously acquired cell information (internal cell information), and performs verification. If the results do not match, location registration is performed on the network 2. When the A-GPS terminal 4 moves to another cell, the cell information received by the communication unit 41 changes. Therefore, by monitoring this change in cell information, the A-GPS terminal 4 changes to another cell. It can be determined whether or not the cell has been moved.

  When the user performs a predetermined input operation for positioning on the A-GPS terminal 4 (occurrence of a positioning event), positioning is started. When the positioning is started, first, the control unit 42 determines whether or not it is the first positioning (step S11). When this determination is “No”, the control unit 42 subsequently determines whether or not the cell information has changed since the previous positioning (step S12). If the determination in step S11 or S12 results in “Yes”, the control unit 42 requests the approximate position from the network 2 via the communication unit 41 (steps S13 and S14). In response to this request, the network 2 supplies the A-GPS terminal 4 with an approximate position (cell position or radio base station position) based on the cell to which the A-GPS terminal 4 currently belongs. The approximate position from the network 2 is received by the communication unit 41 (step S15), and the control unit 42 supplies the received approximate position to the GPS unit 43 and simultaneously holds the approximate position holding unit 46 (step S16). . When the determination in step S12 is “No”, the control unit 42 supplies the approximate position held by the approximate position holding unit 46 to the GPS unit 43 (step S17). Although not shown in FIG. 2, when supplying the approximate position in steps S <b> 16 and S <b> 17, the control unit 42 reads the GPS time from the GPS time holding unit 44 and the navigation message from the navigation message holding unit 45. To the unit 43.

  When the approximate position is supplied in step S16 or step S17 and the GPS time and navigation message are supplied, the GPS unit 43 captures the satellite based on the supplied approximate position and navigation message, and the acquired satellite. The GPS signal from is demodulated based on the supplied GPS time (step S18). The positioning result obtained in this way is supplied from the GPS unit 43 to the control unit 42 (step S19), and positioning is completed. After the positioning is completed, the process returns to step S10 again, and the control unit 42 monitors the change of the cell information.

  As described above, according to the A-GPS terminal of the present embodiment, the approximate position is supplied from the network 2 only when the cell information changes during the first positioning or after the second positioning. The If the cell information has not changed in the second and subsequent positioning, positioning is performed using the approximate position held in the terminal without receiving the approximate position from the network 2. As described above, for the second and subsequent positioning in the same cell, it is not necessary to receive an approximate position from the network 2, and accordingly, the network traffic is reduced, and if data communication is charged, the communication cost is increased accordingly. Can be suppressed. In addition, positioning time is shortened by using the approximate position that is held.

(Second Embodiment)
In the first embodiment described above, for example, as shown in FIG. 3, when the A-GPS terminal 4 is located near the boundary between the cells A and B of the two radio base stations 3a and 3b, It is conceivable that the control unit 42 frequently detects changes in cell information, and as a result, the frequency with which the approximate position is acquired from the network increases.

FIG. 4 shows an example of the operation when the A-GPS terminal is located near the boundary between the two cells A and B. In this example, the cell information is “cell A” → “cell B” → “cell A” → “cell B”.
The operation when changed is shown. In the first “cell A” period, a first position measurement event occurs, and an approximate position based on cell A is received from the network in response to the event occurrence. In the period of “cell A”, a second position measurement event further occurs. In this event occurrence, the approximate position used in the previous positioning is reused. When the third position measurement event occurs in the next “cell B” period, an approximate position based on cell B is received from the network in response to the event occurrence. When the fourth position measurement event occurs in the next “cell A” period, an approximate position based on cell A is received from the network in response to the event occurrence. In the period of “cell A”, a fifth position measurement event is generated. When this event occurs, the approximate position used in the previous positioning is reused. When the sixth position measurement event occurs in the next “cell B” period, an approximate position based on cell B is received from the network in response to the event occurrence. In the period of “cell B”, the seventh to ninth position positioning events are generated, and the approximate position used in the previous positioning is reused in any event. As described above, when the cell information changes frequently, the approximate position is received from the network every time the cell information changes, so the effects of reducing the traffic and cost and shortening the positioning time are reduced.

  Here, an A-GPS terminal capable of reducing the frequency of receiving the approximate position from the network even when the cell information is frequently changed as described above will be described.

  In FIG. 5, schematic structure of the A-GPS terminal which is the 2nd Embodiment of this invention is shown. This A-GPS terminal has the same configuration as the A-GPS terminal shown in FIG. 1, but includes a timer unit 47 for measuring a predetermined time t and cell information broadcast from a radio base station (hereinafter referred to as broadcast cell information). An internal cell information storage unit 48 that stores cell information is added, and broadcast cell information is received from the radio base station at regular intervals, as in the above-described embodiment.

  When receiving the broadcast cell information, the control unit 42 collates the received broadcast cell information with the internal cell information (previously received broadcast cell information) stored in the internal cell information storage unit 48. When the collation results match, the control unit 42 maintains the internal cell information storage unit 48 in the state before receiving the broadcast cell information. When the collation result is inconsistent, the control unit 42 activates the timer unit 47, and the internal cell information storage unit 48 before the timer unit 47 is activated until the timer unit 47 expires. After the time is up, broadcast cell information is received again from the radio base station and collated with the internal cell information stored in the internal cell information storage unit 48. When the collation results after time-up match, the control unit 42 maintains the internal cell information storage unit 48 in a state before time-up. When the collation result after time-up does not match, the control unit 42 stores the cell information received this time in the internal cell information storage unit 48 instead of the internal cell information stored so far.

In this embodiment, the positioning operation is basically performed according to the procedure shown in FIG. 2, but in the determination in step S <b> 12, the control unit 42 stores the internal cell information stored in the internal cell information storage unit 48. Judgment is made as to whether or not it has changed since the previous positioning. A feature of the A-GPS terminal of this embodiment is the positioning operation when the A-GPS terminal is located near the boundary between the two cells A and B and the cell information changes frequently. FIG. 6 shows an example of the operation. This example is also the same as the example shown in FIG. 4, and the broadcast cell information is “cell A” → “cell B” → “cell A” → “cell B”.
The operation in the case of changing is shown. Hereinafter, with reference to FIG. 5 and FIG. 6, the positioning operation in the A-GPS terminal of the present embodiment will be specifically described.

  The first broadcast cell information “cell A” period is the standby period, and the internal cell information “cell A” is stored in the internal cell information storage unit 48 during this standby period. When the first positioning event occurs, the control unit 42 requests the network for an approximate location based on the cell A in response to the occurrence of this event, and in response to this request, the network determines the approximate location based on the cell A to A−. Send to GPS terminal. In the A-GPS terminal, the control unit 42 supplies the approximate position received from the network to the GPS unit 43 and causes the approximate position holding unit 46 to hold it. At the same time, the control unit 42 extracts the GPS time from the GPS time holding unit 44 and the navigation message from the navigation message holding unit 45, and supplies them to the GPS unit 43. The GPS unit 43 performs satellite acquisition using the supplied GPS time, navigation message, and approximate position, and demodulates the GPS signal. In the following description, since the navigation message and the GPS time supply operation are the same, those operations are omitted to simplify the description.

  When a second time positioning event occurs after a certain time has elapsed since the occurrence of the first position positioning event, the control unit 42 first stores the internal cell information stored in the internal cell information storage unit 48 in the previous time. Judge whether it has changed from positioning. In the example of FIG. 6, the second positioning event has occurred during the period of the first broadcast cell information “cell A”, and the internal cell information has not changed. The approximate position used, that is, the approximate position held in the approximate position holding unit 46 is supplied to the GPS unit 43 to perform positioning.

  When the broadcast cell information changes from “cell A” to “cell B” after the occurrence of the second positioning event, the control unit 42 activates the timer unit 7 at the timing of this change, and this activated timer unit Until the time of 7 expires, the approximate position holding unit 46 is maintained in the stored state immediately before the timer is started.

  When a third time positioning event occurs after a certain time has elapsed since the occurrence of the second position positioning event, the control unit 42 determines that the internal cell information stored in the internal cell information storage unit 48 has changed from the previous positioning. Determine if it has changed. In the example of FIG. 6, the third positioning event has occurred during the period of the broadcast cell information “cell B”, but the timer unit 7 is activated, so the internal cell information storage unit 48 has a timer activation. The immediately preceding internal cell information is stored as it is. For this reason, the control unit 42 determines that the internal cell information has not changed, and supplies the approximate position used in the previous positioning, that is, the approximate position held in the approximate position holding unit 46 to the GPS unit 43. Make a positioning.

  When a fourth time positioning event occurs after a certain time has elapsed since the occurrence of the third position positioning event, the control unit 42 determines that the internal cell information stored in the internal cell information storage unit 48 has changed from the previous positioning. Determine if it has changed. In the example of FIG. 6, the fourth positioning event occurs at the timing when the broadcast cell information changes from “cell B” to “cell A”. In this case as well, the timer unit 7 is being activated. The internal cell information storage unit 48 stores the internal cell information immediately before the timer is started. For this reason, the control unit 42 determines that the internal cell information has not changed, and supplies the approximate position used in the previous positioning, that is, the approximate position held in the approximate position holding unit 46 to the GPS unit 43. Make a positioning.

  When the activated timer unit 7 times out after the occurrence of the fourth positioning event, the control unit 42 receives the broadcast cell information from the radio base station and stores the internal cell information stored in the internal cell information storage unit 48. To match. In the example of FIG. 6, the time is up after the broadcast cell information is changed from “cell B” to “cell A”, and both the broadcast cell information and the internal cell information are “cell A”. For this reason, the collation results match, and the control unit 42 maintains the internal cell information storage unit 48 in the storage state before the time is up. As a result, the internal cell information storage unit 48 maintains the state in which the internal cell information “cell A” is stored.

  When a fifth time positioning event occurs after a lapse of a certain time from the occurrence of the fourth position positioning event, the control unit 42 determines that the internal cell information stored in the internal cell information storage unit 48 has changed from the previous positioning. Determine if it has changed. In the example of FIG. 6, the fifth positioning event has occurred during the period of the broadcast cell information “cell A” after time-up, and the internal cell information has not changed. The approximate position used in positioning, that is, the approximate position held in the approximate position holding unit 46 is supplied to the GPS unit 43 to perform positioning.

  After a certain time has elapsed since the occurrence of the fifth position positioning event, when the sixth position positioning event occurs, the control unit 42 changes the internal cell information stored in the internal cell information storage unit 48 from the previous positioning. Determine if it has changed. In the example of FIG. 6, the sixth position measurement event occurs at the timing when the broadcast cell information changes from “cell A” to “cell B”, so the control unit 42 uses the timer unit at the timing of this change. 7 is activated, and the internal cell information storage unit 48 is maintained in the storage state immediately before the activation until the activated timer unit 7 times out. As a result, the internal cell information storage unit 48 maintains the state in which the internal cell information “cell A” is stored. Therefore, the control unit 42 determines that the internal cell information has not changed, and supplies the approximate position used in the previous positioning, that is, the approximate position held in the approximate position holding unit 46 to the GPS unit 43 for positioning. To do.

  When a seventh time positioning event occurs after a lapse of a certain time from the occurrence of the sixth position positioning event, the control unit 42 changes the internal cell information stored in the internal cell information storage unit 48 from the previous positioning. Determine if it has changed. In the example of FIG. 6, the seventh position measurement event occurs in the period of the broadcast cell information “cell B”, but the timer unit 7 is activated, so the internal cell information storage unit 48 has a timer activation. The immediately preceding internal cell information “cell A” is stored as it is. For this reason, the control unit 42 determines that the internal cell information has not changed, and supplies the approximate position used in the previous positioning, that is, the approximate position held in the approximate position holding unit 46 to the GPS unit 43. Make a positioning.

  When the activated timer unit 7 times up after the occurrence of the seventh positioning event, the control unit 42 receives the broadcast cell information from the radio base station and stores the internal cell information stored in the internal cell information storage unit 48. To match. In the example of FIG. 6, since the broadcast cell information is “cell B” and the internal cell information is “cell A”, the collation results are inconsistent, and the control unit 42 has received this time in the internal cell information storage unit 48. The broadcast cell information “cell B” is stored.

  After a certain time has elapsed since the occurrence of the seventh position positioning event, when the eighth position positioning event occurs, the control unit 42 stores the internal cell information stored in the internal cell information storage unit 48 from the previous positioning. Determine if it has changed. In the example of FIG. 6, the eighth positioning event has occurred after the time is up, and the internal cell information storage unit 48 stores internal cell information “cell B” different from the internal cell information “cell A” at the previous positioning. Is stored. Therefore, the control unit 42 determines that the internal cell information has changed, and requests an approximate position based on the cell B from the network. In response to this request, when the network transmits an approximate position based on cell A to the A-GPS terminal, in the A-GPS terminal, the control unit 42 supplies the approximate position received from the network to the GPS unit 43 for positioning. The approximate position is held by the approximate position holding unit 46.

  After a certain time has elapsed since the occurrence of the eighth position positioning event, when the ninth position positioning event occurs, the control unit 42 determines that the internal cell information stored in the internal cell information storage unit 48 has changed from the previous positioning. Determine if it has changed. In the example of FIG. 6, the ninth positioning event has occurred during the period of the broadcast cell information “cell B” after time-up, and the internal cell information has not changed. The approximate position used in the positioning, that is, the approximate position held in the approximate position holding unit 46 is supplied to the GPS unit 43 to perform positioning.

  According to the positioning operation described above, when the broadcast cell information changes from “cell A” to “cell B” and then immediately changes to the original “cell A”, the internal cell information storage unit 48 The state where “cell A” is stored as the cell information is maintained. During this time, the approximate position held in the terminal is used, and it is not necessary to newly acquire the approximate position from the network, so that the communication frequency can be reduced accordingly. In the example of FIG. 4, the approximate position is acquired from the network every time the broadcast cell information changes, so the approximate position is acquired four times. However, in the example of FIG. 6, the approximate position is acquired two times. The communication frequency is halved.

  In the example shown in FIGS. 4 and 6, the position measurement event occurs at regular intervals, but may occur at irregular intervals. As an example in which the positioning event is generated at regular intervals, when the user performs an input operation for starting positioning, the positioning event is generated at regular intervals. As an example in which a positioning event occurs at an indefinite interval, a positioning event occurs every time a user performs an input operation for starting positioning.

Next, the predetermined time measured by the timer unit 47 will be described. This predetermined time is determined based on the cell radius L, the maximum allowable initial position error A of the A-GPS terminal, and the allowable moving speed v of the A-GPS terminal assumed as a communication service in the wireless area. The maximum allowable initial position error A is a difference between the actual position of the A-GPS terminal and the given approximate position, and the A-GPS terminal can normally perform positioning using the given approximate position. Expresses the tolerance. Generally, the cell radius L <the maximum allowable initial position error A, and the approximate position cannot be input beyond the maximum allowable initial position error A. Here, as shown in FIG. 7, consider a case where the A-GPS terminal 4 belonging to the cell A (cell radius L) of the radio base station 3 moves to another cell at an allowable movement speed v. In this case, the range in which the A-GPS terminal 4 can use the estimated position 6 based on the cell A beyond the cell A is a range that does not exceed the maximum allowable initial position error. Let t be the elapsed time from the time when the cell is changed to another cell.
L + vt <A
The relationship holds. Therefore, the elapsed time t is
t <(AL) / v
Given in. Since the GPS performance is not affected if the elapsed time t satisfies this condition, the predetermined time measured by the timer unit 47 is the elapsed time t.

  In each embodiment described above, the A-GPS terminal can be configured by a computer system including processing means and storage means. The control unit 42 corresponds to a processing unit, and the navigation message holding unit 45, the approximate position holding unit 46, and the internal cell information storage unit 48 correspond to a storage unit. The control of the series of positioning operations by the control unit 42 is realized by the processing means executing a program stored in advance in the storage means. For example, in the first embodiment, the cell information received by the communication unit in the process of receiving cell information in the cell currently belonging to the communication unit, when performing the first GPS positioning, or in the second and subsequent GPS positionings Is different from the previous GPS positioning, the approximate position is obtained from the network and held in the holding unit, and the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning In the program, processing using the approximate position held in the holding unit as assist data is executed by the program. In the second embodiment, the communication unit causes the communication unit to receive the cell information in the cell that currently belongs, the cell unit received by the communication unit stores the cell information as internal cell information in the storage unit, and the communication unit When the received cell information is different from the internal cell information that is the previously received cell information stored in the storage unit, a timer unit that measures a predetermined time is started, and the timer that has been started up until the time is up During the interval, the process of maintaining the state in which the internal cell information, which is the cell information received last time, is stored in the storage unit as it is, is stored in the storage unit when performing the first GPS positioning, or after the second GPS positioning. If the internal cell information is different from the previous GPS positioning, the approximate position is acquired from the network and held in the holding unit, and stored in the storage unit in the second and subsequent GPS positioning. If the same internal cell information and the previous GPS positioning, such as the process of using the approximate position held in the holding section as the assist data is performed by the program.

  Further, in the A-GPS terminal of each embodiment, the control unit 42 supplies the positioning result obtained by the GPS unit 43 to the positioning server 1 or other server arranged in the network 2 to provide various services via the network. It is also possible to use it.

  The actual usage of the A-GPS terminal of each embodiment includes a card type (or chip), a mobile phone, a mobile phone, a navigation system such as a mobile terminal, and a PDA. Various usage forms such as the one can be considered.

It is a block diagram which shows schematic structure of the A-GPS terminal which is the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the A-GPS terminal shown in FIG. It is a schematic diagram which shows the state in which the A-GPS terminal shown in FIG. 1 is located in a cell boundary part. It is a timing chart for demonstrating operation | movement of the A-GPS terminal of the state shown in FIG. It is a block diagram which shows schematic structure of the A-GPS terminal which is the 2nd Embodiment of this invention. It is a timing chart for demonstrating operation | movement of the A-GPS terminal shown in FIG. It is a schematic diagram for demonstrating the measurement time of the timer part in the A-GPS terminal shown in FIG. It is a figure for demonstrating the conventional A-GPS terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioning server 2 Network 3, 3a, 3b Wireless base station 4 A-GPS terminal 5 GPS satellite 6, 102, 103 Approximate position 41 Communication part 42 Control part 43 GPS part 44 GPS time holding part 45 Navigation message holding part 46 Approximate position Holding unit 47 Timer unit 48 Internal cell information storage unit 100, 101 Portable terminal

Claims (11)

A network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. There,
A holding unit for holding the approximate position;
A GPS unit that performs the GPS positioning based on the assist data;
A communication unit capable of receiving, in each cell, cell information capable of identifying the own cell broadcasted in each of the plurality of cells;
When performing the first GPS positioning, or when the cell information received by the communication unit in the second and subsequent GPS positioning is different from the previous GPS positioning, the approximate position is acquired from the network, and the acquisition is performed. When the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position is supplied to the GPS unit and held in the holding unit. A network-assisted GPS terminal having a control unit that supplies the approximate position held to the GPS unit. A network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance. There,
A holding unit for holding the approximate position;
A GPS unit that performs the GPS positioning based on the assist data;
A communication unit capable of receiving, in each cell, cell information capable of identifying the own cell broadcasted in each of the plurality of cells;
A storage unit for storing cell information received by the communication unit as internal cell information;
A timer unit for measuring a predetermined time;
When the cell information received by the communication unit is different from the previously received cell information stored in the storage unit, the timer unit is activated, and the activated timer unit times out A control unit that maintains the state in which the internal cell information, which is the cell information received last time, is stored in the storage unit.
When the control unit performs the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positioning, the approximate position from the network And the obtained approximate position is supplied to the GPS unit and held in the holding unit, and the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning. In this case, a network assist type GPS terminal that supplies the GPS unit with the approximate position held in the holding unit. The network-assist GPS terminal according to claim 2, wherein the approximate position is a center position of a cell to which the current position belongs. The predetermined time includes v that is an allowable movement speed of the network-assisted GPS terminal that is assumed in advance in the wireless area, L that is a radius of a cell that currently belongs, and an approximate position that is held in the holding unit. The maximum allowable initial position error capable of GPS positioning expressed as a difference between A and A, the time since the cell information received by the communication unit changed from the information of the currently belonging cell to the information of another cell If time is t,
t <(AL) / v
The network-assisted GPS terminal according to claim 3, which is given by an elapsed time t that satisfies the following condition. A network-assisted GPS terminal according to any one of claims 1 to 4,
A position positioning system, in which position information of a plurality of cells constituting a radio area is registered in advance, and the GPS terminal supplies a network that supplies position information of a cell to which the terminal currently belongs. In a network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance A positioning method to be performed,
A communication unit provided in the GPS terminal and capable of receiving in each cell the cell information capable of identifying its own cell broadcasted in each of the plurality of cells receives the cell information in the cell to which it currently belongs. And steps to
When the control unit provided in the GPS terminal performs the first GPS positioning, or when the cell information received by the communication unit in the second or subsequent GPS positioning is different from the previous GPS positioning, the network If the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position is acquired from the holding unit provided in the GPS terminal, Using the approximate position held in the holding unit as the assist data. In a network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance A positioning method to be performed,
A communication unit provided in the GPS terminal and capable of receiving in each cell the cell information capable of identifying its own cell broadcasted in each of the plurality of cells receives the cell information in the cell to which it currently belongs. And steps to
A storage unit provided in the GPS terminal stores the cell information received by the communication unit as internal cell information;
The control unit provided in the GPS terminal is provided in the GPS terminal when the cell information received by the communication unit is different from the internal cell information which is the previously received cell information stored in the storage unit. Starting the timer unit that measures the predetermined time, and maintaining the state in which the internal cell information, which is the cell information received last time, is stored in the storage unit as it is until the started timer expires When,
When the control unit performs the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positionings, the approximate position from the network Is acquired and held in the holding unit provided in the GPS terminal, and the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the And a step of using the stored approximate position as the assist data. The position positioning method according to claim 7, wherein the approximate position is a position of a center of a cell to which the current position belongs. It is expressed as the difference between the estimated position and the approximate position held in the holding unit, where v is the allowable movement speed of the network-assisted GPS terminal assumed in the wireless area, L is the radius of the cell that currently belongs. The maximum allowable initial position error capable of GPS positioning is A, and t is the elapsed time from the time when the cell information received by the communication unit changes from the information of the currently belonging cell to the information of another cell. In case,
t <(AL) / v
The position positioning method according to claim 8, wherein an elapsed time t that satisfies the condition is set as the predetermined time. In a network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance A program used,
A process for causing a communication unit capable of receiving in each cell cell information capable of specifying its own cell broadcasted in each of the plurality of cells to receive the cell information in a currently belonging cell;
When the first GPS positioning is performed, or when the cell information received by the communication unit in the second and subsequent GPS positioning is different from the previous GPS positioning, the approximate location is obtained from the network and the GPS terminal When the cell information received by the communication unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position held in the holding unit is stored in the assist data. A program for causing a computer of the GPS terminal to execute processing used as In a network-assisted GPS terminal that acquires position information of a cell that currently belongs as an approximate position, which is one of assist data for performing GPS positioning, from a network in which position information of a plurality of cells constituting a wireless area is registered in advance A program used,
A process for causing a communication unit capable of receiving in each cell cell information capable of specifying its own cell broadcasted in each of the plurality of cells to receive the cell information in a currently belonging cell;
Processing to store the cell information received by the communication unit in the storage unit as internal cell information;
When the cell information received by the communication unit is different from the internal cell information which is the previously received cell information stored in the storage unit, the timer unit for measuring a predetermined time is activated, and the activated timer is Until the time is up, a process of maintaining the state in which the internal cell information which is the previously received cell information is stored in the storage unit, and
When performing the first GPS positioning, or when the internal cell information stored in the storage unit is different from the previous GPS positioning in the second and subsequent GPS positioning, the approximate position is acquired from the network and retained. When the internal cell information stored in the storage unit in the second and subsequent GPS positioning is the same as the previous GPS positioning, the approximate position stored in the holding unit is used as the assist data. Is executed by the GPS terminal computer.

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